Modified version of the COSMO-SAC model for the prediction of vapour-liquid equilibria of mixtures containing halogen compounds

Abstract

• COSMO-SAC (+OH-Cl), (+OH-Br) and (+OH-ClBr), extensions of the COSMO-SAC model were developed to take into account hydrogen bonds formed with chlorine or bromine atoms, in particular in mixtures containing deep eutectic solvents and water, alcohols or carboxylic acids. • The new parameters of the extended models were optimized with a data base of 1402 vapour-liquid data points. • Performances were tested with vapour-liquid, liquid-liquid and solid-liquid databases with 2237, 787 and 503 data points, respectively. • Improvements of the prediction of the vapour-liquid equilibria for mixture containing halogens atoms were obtained. • Comparisons between the results from the three extended models showed that the distinction between chlorine and bromine atoms in terms of hydrogen bonds was not necessary within the COSMO-SAC models. In this work, the prediction of the phase behaviour of mixtures containing chlorine or bromine atoms involved in hydrogen bonding is investigated. Based on the COSMO-SAC (2010) model, extended models named COSMO-SAC (+OH-Cl), COSMO-SAC (+OH-Br) and COSMO-SAC (+OH-ClBr) are presented. The extension of the base model focuses on the hydrogen bond contribution. For this contribution, the addition of two parameters in an empirical equation introduces a dependence in temperature. The parameters were optimized using a databased composed of vapour-liquid equilibria data of mixtures comprised of both ionic liquids or deep eutectic solvents and regular compounds. The mixtures always involve halides or halocarbons as well as molecules of water, alcohol or carboxylic acids. The extended models are shown to improve the predictions of such systems for vapour-liquid equilibria as well as being able to keep providing satisfying results for both liquid-liquid and solid-liquid equilibria.